The speaker views Dorothy as this innocent being whom doesn't understand the depth of nature as he has grown to understand it. After five years the speaker no longer has the same perception of the world, unlike Dorothy he has grown and learned to look at nature from a more mature point of view. Dorothy unfortunately possesses this innocent mind which still captures nature with the joy a child may have. He completely seems to underestimate her because she is a woman. Wordsworth writes, in lines 112-120: "Nor perchance,
If I were not thus taught, should I the more
Suffer my genial spirits to decay:
For thou art with me here upon the banks
Of this fair river; thou my dearest Friend,
My dear, dear Friend; and in thy voice I catch
The language of my former heart, and read
My former pleasures in the shooting lights
Of thy wild eyes. Oh! yet a little while
May I behold in thee what I was once,"
In other words he is no longer capable of thinking in such a childlike manner he has to turn to his sister, with her "wild eyes" and hope to relive this pleasure. This implies that he...